I can't tell you what the root cause of the issue is, but I'm not having it, provided I arrow in to the combo box options after expanding before I use first letter nav.
In the case of the states listed, once I've arrowed in, using the letter K in that combo box keeps bouncing me between KS and KY.
Brian - Windows 10 Pro, 64-Bit, Version 20H2, Build 19042
Any idiot can face a crisis. It's the day-to-day living that wears you out.
~ Anton Chekhov